The CCC of the RCC disagrees with you....or rather, you disagree with the CCC of the RCC.
841 The Church's relationship with the Muslims. "The plan of salvation also includes those who acknowledge the Creator, in the first place amongst whom are the Muslims; these profess to hold the faith of Abraham, and together with us they adore the one, merciful God, mankind's judge on the last day."330This means that the Mohammedans hold an incomplete image of God. Obviously, they're not Trinitarians, since they reject the divinity of Christ. When they acknowledge "the Creator" and "mankind's judge," they are acknowledging the God of Christianity, although with an imperfect understanding.
The same could be said of the ancient Greeks who only knew God as the "Prime Mover." Inasmuch as they acknowledged the Prime Mover, they were acknowledging God, but with an imperfect understanding. St. Paul said as much.
Paul then stood up in the meeting of the Areopagus and said: “People of Athens! I see that in every way you are very religious. For as I walked around and looked carefully at your objects of worship, I even found an altar with this inscription: TO AN UNKNOWN GOD. So you are ignorant of the very thing you worship—and this is what I am going to proclaim to you.